Fabrication of porous and magnetic Fe/FeNX fibers by electro-blown spinning method for efficient adsorption of Cr (VI) ions

A novel porous and magnetic Fe/FeNX composite fibers for Cr (VI) ions adsorbent were prepared by electro-blown spinning technology coupled with high temperature nitrided way. The X-ray Diffraction (XRD) and Differential Scanning Calorimetry-Thermo Gravimetric Analyzer (DSC-TGA) revealed metallic iron and FeNX mainly existed in these fibers. Furthermore, the effect of spinning voltage, air pressure and solution concentration on the morphology for the as-spun fibers were investigated. Meanwhile, the effect of calcination temperature on morphology and structure, crystalline property and hysteresis loop also were discussed. The obtained fibers had a uniform morphology and structure, and a high specific surface area (151 m2 g−1) during the calcination temperature of 800 °C. The Fe/FeNX fibers showed effective sorption affinity for Cr (VI) ions, achieving maximum adsorption capacities of 79.21 mg/g at 25 °C. It mainly was ascribed to the existence of metallic iron in the obtained fibers. Meanwhile, the FeNX contents in the fibers were extremely beneficial to the adsorbent recovery.